A touch panel, which is an input/output means for detecting a touch position of a user on a display screen and receiving information on the detected touch position to perform an overall control of an electronic device including a display screen control, is a device which recognizes touch as an input signal when an object such as a finger or a touch pen is touched on the screen.
The touch input device has been frequently mounted on a mobile device such as a mobile phone, a personal digital assistant (PDA), and a portable multimedia player (PMP) in recent years. In addition, the touch input device is used throughout overall industries, such as a navigation, a netbook, a notebook, a digital information device (DID), a desktop computer using an operating system that supports touch input, an internet protocol TV (IPTV), a state-of-the-art fighter, a tank, and an armored vehicle.
The touch panel is designed to be added on or embedded in a display device such as a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting diode (OLED), or an active matrix organic light emitting diode (AMOLED).
The touch panel is optically transmissive and includes detecting units employing a conductive material.
The detecting units are formed in repetitive patterns in order to recognize the position of an input signal on the touch panel. In this case, there is a problem that as detecting layers including the detecting units are laminated in parallel, the patterns overlap each other and therefore a moire phenomenon occurs due to interference between the patterns.
There are proposed methods in which, when patterns constituting detecting electrodes overlap each other due to the stack of detecting substrates or the stack of the detecting substrate and an image display panel, torsion based on a predetermined angle is applied between the patterns to prevent the occurrence of a moire pattern, thereby solving a problem that visibility is deteriorated due to the moire pattern.
Korean Patent Application Publication No. 10-2010-0129230 has disclosed a method in which the sidewall formation of mesh patterns is controlled in a conductive layer constituting detecting units, thereby reducing the occurrence of moires.
In a process of forming the conductive layer, a photoresist material is proximity-exposed through a photomask disposed with a proximity gap of 70 to 200 μm, and periodic patterns corresponding to periodically repeated mask patterns of the photomask are formed.
First and second conductive thin metal wires constituting the conductive layer have protruding portions at sides thereof, and the protruding portions extend toward an opening from a virtual line indicating a designed width of the thin metal wire. The protruding amount of the protruding portion is 1/25 to ⅙ of the designed width.
In the prior art, the sidewall formation of the mesh patterns is controlled, thereby reducing the occurrence of moires. However, since the control of the forming position is done by the control of mask disposition, it is difficult to accurately control fine patterns of the protruding portion as the line width of the conductive layer decreases. Therefore, it is difficult to uniformly suppress the occurrence of the moire phenomenon over the entire region.